Surely, the technology to slice up a diamond or emerald is a bit complicated…
Don’t you need a magnifying glass to see fissures etc?
Depending on your age and eyesight, you may or may not need amplification to see flaws. I do. My younger colleagues do not.
The first gem was probably cut over 2000 years ago. They really didn’t care much about the exactness of the cut or the style. Advertising hadn’t been invented yet. Simply cutting it and polishing the facets so that they refracted light was enough.